In general, the air conditioner is provided with a refrigerating cycle including a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger, basically. In detail, in the refrigerating cycle, gaseous refrigerant compressed at the compressor is introduced to the outdoor heat exchanger and involved in a phase change from the gaseous refrigerant to liquid refrigerant while discharging heat to an outside of the outdoor heat exchanger. Then, the liquid refrigerant from the outdoor heat exchanger is expanded while passing through the expansion valve, and, therefrom, introduced to the indoor heat exchanger.
Then, the refrigerant introduced to the indoor heat exchanger is involved in a phase change from the liquid refrigerant to the gaseous refrigerant. A likely, the refrigerant absorbs heat from an outside of the indoor heat exchanger while the refrigerant is involved in a phase change.
And, the air conditioner may be provided with an outdoor unit installed in an outdoor space and an indoor unit installed in a room space. The outdoor unit may have the compressor for compressing the refrigerant, the outdoor heat exchanger and the fan for heat exchange of the refrigerant with outdoor air, and various kinds of pipelines for connecting the compressor to the indoor unit. The indoor unit may have the indoor heat exchanger and the expansion valve for heat exchange of the refrigerant with room air.
In the meantime, the outdoor unit with a plurality of the indoor units connected thereto has a large sized outdoor heat exchanger mounted thereto for increasing a heat exchanger area, a compressor, an oil separator, and an accumulator for the refrigerant circulating an air conditioning cycle, a fan for forced flow of the air and a motor for rotation of the fan mounted thereto, and a plurality of pipelines for connection among different elements and the indoor unit housed in the outdoor unit.
FIG. 1 illustrates a conceptual drawing of a velocity triangle of an axial flow fan mounted to an outdoor unit of a related art air conditioner.
Referring to FIG. 1, W1 denotes a relative velocity of air being introduced to the axial flow fan 10, W2 denotes a relative velocity of the air being discharged from the axial flow fan 10, u denotes a rotation velocity of a blade of the axial flow fan, V1 denotes an absolute velocity of the air being introduced to the fan, V2 denotes an absolute velocity of the air being discharged from the fan, Vm2 denotes an axial velocity component of the axial flow fan 10, and β1 and β2 denote an inlet angle and an outlet angle of the blade 11, respectively.
The axial flow fan produces an axial flow A, and, in a velocity component u of the air being discharged from the axial flow fan 10, a ratational velocity component Vu2 produced by rotation of the axial flow fan 10 in a rotation direction thereof is a loss produced without relation to work of the axial flow fan 10, which drops efficiency of the axial flow fan 10.